Climate change threatens us with increased risk of drought, flood and tempest, leading to mass migration and conflict. These dangers can be limited if the rise in temperature is less than 2˚C above the pre-industrial level.
And in 2010 world leaders agreed at Cancun to act to achieve that limit. But the commitments made since then have little chance of achieving that target. Even if every promise was carried out, carbon-dioxide emissions will continue to rise (see Figure). By 2035 the concentration of carbon dioxide in the atmosphere will exceed the critical level for a 2˚C rise in temperature and on current policies the temperature will eventually reach 4˚C above the pre-industrial level. This is the
central forecast, implying a 50% chance of still higher temperatures. We must take action to prevent this, by radically cutting the world’s output of carbon dioxide (see Figure). We must reduce the use of energy and we must make the energy we use clean i.e. free of carbon-dioxide emissions. This Report is about how to make energy clean.